Production systems and contributions of grain legumes to soil health and sustainable agriculture: A review

Sustainable development of agriculture is essential, and there is unanimity that diversification of the cropping systems could support sustainable production. Grain legumes are essential in farming systems in terms of food and nutrition security and income generation. Under legume-based cropping systems, these crops are a potential remedy to pest and disease issues, low nutrient supply, biodiversity protection, and food and nutrition insecurity. In this chapter, we highlight the production systems of legumes and their use in sustainable agricultural production. Specifically, we have looked at the benefits of having a legume cropping system in the agroecosystem, production, and farming systems. The function of legumes in improving the potential of crop productivity is a promising approach to tackling the challenges of poor crop yields and improvement in sustainable production. Due to health and environmental benefits, the focus should shift to breeding grain legumes that can fully express their biological nitrogen fixation and other potentials under abiotic and biotic limitations

Effect of Legume Extracts on Germination, Seedling Health of Beans (Phaseolus vulgaris L.) and Soil Microorganisms

Application of undecomposed green manure has been reported to cause poor emergence and establishment of common beans in the field. Therefore, to understand the mechanisms’ contributing to the poor crop establishment, the effect of extracts from fresh and decomposed legume green manures on bean seed germination, fungal mycelial growth, spore germination and germ tube elongation were evaluated. The extracts were prepared in either ethanol or distilled water. Data was collected on percentage seed germination, seedling length, mycelial radial growth, spore germination and germ tube elongation. Ethanol extracts from fresh lablab inhibited bean germination by 56%, increased mean germination time to 8 days, and decreased germination index while ethanol extracts of groundnut and beans caused highest inhibition in bean shoot length and reduced biomass. Ethanol extracts from fresh green manures significantly inhibited fungal mycelial growth while the aqueous extracts from beans, groundnuts and soybean had significant level of antifungal activity while aqueous lablab extracts stimulated mycelial. Aqueous extract of lablab and soybean enhanced spore germination by over 70% with more pronounced effect on germ tube length and number of germ tubes by 8.0% and 13% respectively. The study comparatively reveals that the extract of lablab was inhibitory to common bean germination compared to other legume extracts and also stimulated the growth of root rot pathogens that may have resulted in poor establishment of beans

A Method for Selection of Coffee Varieties Resistant to <i>Fusarium stilboides</i>

Fusarium bark disease (FBD) of coffee caused by Fusarium stilboides Steyaert has been associated with yield losses and tree death in coffee-growing countries, including Kenya. Varietal resistance is of utmost importance in managing the disease, and the continued increase in host resistance is considered sufficient to control the disease. Therefore, this study investigated the response of four coffee cultivars to F. stilboides. Fifteen hypocotyls from Coffea arabica (Ruiru 11, Batian and SL 28), plus two other coffee species, Coffea canephora (Robusta coffee) and Coffea liberica (Liberica coffee), were inoculated with various concentrations of three F. stilboides isolates (NRF 930/18, TN002B (I), BS008B (A)) using both the injection and drenching methods. The stem injection method was performed by injecting one microliter of the F. stilboides spore solution into the hypocotyl. In the drenching method, coffee seedlings had their roots cut and transplanted in a transplanting mixture, after which 10 mL of the F. stilboides spore solution was applied to the soil surface in each pot. The inoculated hypocotyls were incubated at 24 ± 2 °C for 105 days. The plants were watered regularly as necessary while the development of symptoms was observed and assessed weekly. Disease severity was evaluated using a modified scale of 0–4, while incidence was scored as a percentage of infected seedlings. Coffee seedlings inoculated with F. stilboides developed symptoms such as wilting, stunted growth and defoliation. In the first season, the coffee cultivars of Ruiru 11 and Liberica inoculated with Fusarium stilboides had pronounced severity compared to other cultivars. In the second season, the coffee cultivars Batian and Ruiru 11 had pronounced severity compared to other cultivars. The isolate TN002B (I) was observed to be highly virulent as compared to other isolates. The variation in response to disease infection exhibited by the four cultivars presents a key input in breeding programs for resistance to F. stilboides